woodward



(No Model.)

L. MUTHER & R. G. WOODWARD. TRIMMER FOR SEWING MACHINES.

No. 369,653. Patented Sept. 6, 1887.,

N. PETERS. Phnw-Liihographer, Washington, DLC.

NITED STATES PATENT FFIQE.

LORENZ MUTHER AND RUSSEL G. VVOODWARD, OF CHICAGO, ILLINOIS, ASSIGNORS TO THE UNION SPECIAL SEWING-MACHINE COMPANY, OF

SAME PLACE.

TRIMMER FORSEWING-IVIACHINES.

SPECIFICATION forming part of Letters Patent No. 369,653, dated September 6, 1887.

Application filed November 16, 1886. Serial No. 218,997.

To all whom it may concern:

Be it known that we, LORENZ MUTHER and Russian G. WOODWARD, both of Chicago, in the State of Illinois, have invented certain new and useful Improvements in Sewing-Machine Trimmers, whereof the following is a specification, reference being had to the accompanying drawings.

In said drawings, Figures 1, 2, 3, and 4. repro resent a vertical section through the clothplate of a'sewing-machine and a side elevation of the trimmer in the four different positions assumed by it at the respective quadrants of the driving-shafts rotation, certain adjacent parts of the stitch-forming mechanism being also shown to indicate the relation of the trimmer thereto. Fig. 5 is a top or plan view of that portion of the cloth-plate which is immediately adjacent to the trimmer.

Fig. 6 is a side view of the trimmer-knife detached, and Figs. 7 and 8 are respectively top and side views of the devices for securing and adjusting the knife.

It is not deemed necessary to show or de scribe the general construction of the sewingmachine; but we refer to our Letters Patent Nos. 299,568 and 299,569, dated June 3, 1884, as embodying a form of machine well adapted for use with our improved trimmer.

Our improvements relate to that class of trimmers wherein a single blade extending through the cloth-plate is caused to reciprocate in a vertical plane parallel to the line of feed and adjacent to the needle, the purpose 3 5 of the invention being to obtain the freest possible action of the knife, to simplify its attachment to the driving mechanism, and to permit its adjustment toward and from the needle.

In the drawings, A represents the main driving-shaft of the sewing-machine; B, the cloth-plate; B, the detachable portionthereof, now commonlyused in proximity to the needle, 850.; C, the feed'dog; D, the head; E, the needle-bar; F, the needle; G, the presser foot; H, the resser-foot bar, and I the cloth or material operated upon.

The trimmer-knifc L has its cuttingedge (No model.)

slightly inclined, as shown, and extends down through a narrow slot, 25, whose relation to the other parts is indicated in Fig. 5, where B is the detachable portion of the cloth-plate containing the feed-slots u and needle-hole1l, and secured to the main plate 13 by means of screws j. P is a second detachable portion of the cloth-plate, containing the knife-slott, and having a depressed projection, 0, (shown in dotted lines,) whose upper surface fits beneath the plate B. The detachable plate P is secured by screws 8 and r, the former of which extends through a slot, 19, of the plate B into the projection 0, and the latter of which extends through a similar slot, q, in the opposite ends of the plate P itself into an under hanging lug on the main plate B. The end of a slide, R, of the ordinary construction abuts against the other edge of the plate P, thus forming the continuation of the cloth-plate on that side, and said slide moves in the usual manner toward or from the edge of plate P. The slots 1) and q permit the lateral adjustment of the plate P, (the slide B being moved accordingly,)and thus the distance of the knifeslot if from the needle may be varied, and said slot, being entirely within the plate P, can be made of a width barely sufficient for the knife to enter. A vertical strip, m, about onefourth of an inch in height, extends at an angle from the side of the knife-slot for a short distance back, its purpose being to deflect the cut-off portion or waste away from the working parts.

Returning, now, to the other figures, we will describe the attaching and driving niechanism of the trimmer.

The knife L fits snugly but freely in a slot, (1, Fig. 7, formed in the front end of the arm K,where it is hung upon a pin, 1), having near its head a circumferential groove, 0, in which rests the free end of a curved spring, 9, mounting on the side of the arm K. By this means we suspend the knife freely, so that it may swing slightly on the pin bin a vertical plane, for a purpose to be hereinafter explained, and we avoid the use of a screw attachment,which is troublesome to handle when the knife is to LII be removed and replaced. The pin 11 can be instantly withdrawn or inserted and the knife detached or reattached without the least trouble, and the spring 9, resting in the groove 0, prevents any accidental displacement. The arm K is made in two pieces, as shown more clearly in Fig. 7, having lateral projections M N, respectively, the former of which has a groove, f, and the latter a rib, a, fitting therein. A screw, 6, extends through a slot in the part M into the part N, and thus the lateral adj ustment of the front end ofthe arm K may be effected by the movement of the part M relatively to the part N. This lateral adjustment of the knifecarrier is of course to be accompanied by a similar movement of the plate P, which contains the knife-slot t. The arm K is pivoted at a to a downwardlydepending piece, T, mounted upon the head D, and power is applied to the arm K by means of a connecting-rod, J, extending up through a slot, h, in the cloth-plate and vertically reciprocated by an eccentric, U, on the driving-shaft A.

The operation of the trimmer is as follows Referring to Fig. 1, it will be seen that the arm K and knife L are in their lowest positions, and that the feed-dog O is entirely beneath the surface of the cloth-plate and about to coinmence its upward movement. The edge of the knife is in contact with the fabric'I at the end of the last preceding out. In Fig. 2 the driving-shaft A- has rotated a quadrant, and the knife L is therefore halfway up. The feeddog also has risen into contact with the fabric and has commenced its forward movement. In Fig. 3 the driving-shaft has rotated another quadrant, the knife is entirely up, and the forward movement of the feed is completed. If the knife had been rigidly attached to the arm K, instead of being freely suspended thereon, it would during the feed movement have been compelled by its angular relation to the arm to assume the position shown in the dotted lines, and would have therefore interfered with the feed by pressure against the uncut part of the fabric, so that the latter would have been buckled up and dragged. The capac-- ity of the knife to swing on its pivot 7) permits the fed fabric to push it back into the position shown by the solid lines of Fig. 3 without appreciable retardation and by the time the feed is complete. The knife is now in its rearmost position and the cut is made, as shown in Fig. Lwhich represents the fourth quad rant of the driving-shafts rotation.

The advantages of this mode of operating the knife are as follows: It is well known that a trimmer with an inclined edge will cut more easily than with a horizontal one, for the obvious reason that a drawing out is accomplished with less expenditure of power than a punching or chiseling out. For use upon hosiery and similar fabrics it is desirable that the angle of the cutting-edge to the plane of the fabric should be obtuse, or more than forty-five degrees, in order that the cutting may be protracted. It is also desirable for mechanical reasons that the trimmer-cutter should bedriven from the main shaft of the machine by means of a connecting-rod and pivoted lever arm such as we employ, attachment to the needle-bar or other driven part having been found highly wasteful of power and inefficient. While, however, the use of the pivoted lever as the knife-carrier has been common, the knife has always been rigidly attached thereto or has been provided with guides above and below the cloth-plate. Such rigid attachment has necessitated the use of an edge inclined at an acute angle (or at most forty-five degrees) to the plane of the fabric, or, if a more obtuse angle was used, the edge has obstructed the feed, as explained above in connection with Fig. 3. The use of guides to prevent the knife from moving in an arc adds greatly to the friction,and in the 11mited space about the stitch-forming mechanism such complication of parts is undesirable. While these elements of operation seem to the careless observer trifling, they become serious when the main driving-shaft of the machine is run, as in present practice, at the rate of two thousand five hundred or three thousand revolutions per minute.

In our improved trimmer the use of a very obtusely-inolined edge is permitted upon a driving mechanism of the simplest and strongest construction without impeding the feed movement. The other features of improvement,which relate to the removal of the knife and its adjustment toward and from the needle, have already been described.

We do not claim, broadly, the use of a knife with an inclined edge, nor the mounting of the knife upon a lever-arm reciprocated from the driving-shaft, save when the knife is freely suspended from said arm. Furthermore, we are aware that various devices have been employed for adjusting the knife toward and from the needle, and that an adjustable plate has been used with such knives, the edge of said plate forming one edge of the knife-slot. Our adjustable plate I? differs from such former devices in that the knife-slot is entirely inclosed by it, and hence does not vary in width with each adjustment of the plate, as was necessarily the case where the movable plate formed only one edge of the slot. The wide slot made by moving the old forms of plate from the needle not only permitted the pushing down of dirt, and sometimes of the fabric itself, below the cloth-plate, but with a freelysuspended knife would endanger the knife itself by allowing it to play laterally.

We claim- 1. The combination, with the stitch-forming mechanism, of a pivoted lever-arm arranged to oscillate in a vertical plane, aknife having an inclined edge, freely suspended from said lever-arm, and extending down through the IOO work-plate, and driving mechanism for said justable plate P, entirely iuclosing the knifelever-arm, substantially as set forth. slot, substantially asset forth.

2. The combination, with the lever-arm K, LORENZ MUTHER. having a slot, d, in its front end, 'ofthe knife RUSSEL G. WOODWARD. 5 L, pin 1), having a grooved neek,and the spring Witnesses to signature of L. Mather:

9, bearing against said pin,substautially as set H. O. 'WILSO, forth. E. P. HATCH.

3. The combination of the lever -arn1 K, \Vitnesses for Russel G. VVoodWard: havingalaterally-adjustable portion,the knife \V. S. NORTH,

to L, suspended therefrom, and thelaterallyad C. MONEIL. 

